During the pilot hole drilling, Michels implored to Phillips 66 to allow the crews to move to a 24/7 work schedule on its property to ensure the integrity of the hole was intact. This was due to the changing soil and drilling conditions.
Houston Ship Channel
As the horizontal directional drilling (HDD) industry continues to mature and expand, so too do the lengths and diameters of the projects this trenchless method is applied to every day. How far can they go? A handful of HDD contractors are qualified to expertly handle such immense and challenging projects, proving that the HDD industry appears to know no bounds.
Directional Crossings is one such HDD contractor that has become known for handling long crossings in difficult jobsite conditions. The Houston Ship Channel project, which the Brownsville-Wis. contractor completed earlier this year, is one such project. This project is described as a record-setting HDD installation for an 18-in. steel gas pipeline for energy giant Phillips 66, reaching what was once thought to be an unachievable distance of 12,459 ft.
The Houston Ship Channel Project is the 2015 Trenchless Technology
Project of the Year for New Installation.
Drilling northeast to southwest, Michels used the now commonly-used intersect method to complete the project, except they didn’t as the two pilot hole pipes actually connected tip-to-tip, not requiring the contractor to adjust to make that final connection. The project brings a pipeline along a direct route from Scott Bay in Baytown, Texas, to Kinder Morgan Energy Partners’ Battleground Oil Specialty Terminal Co. (BOSTCO) in LaPorte, Texas, averting a costly re-route that may have allowed a more standard HDD crossing location.
The project required a ton of planning before the first drill rod was in the ground, including precision, pinpoint knowledge of what was already buried in the channel, as well as a plan to keep full circulation during pullback. The project took two years to design, plan and permit, with safety being of primary importance.
“This was all done in a very congested corridor. … Hitting it on the tips was pretty amazing,” says Tim McGuire, vice president at Michels Directional Crossings at Michels Corp. “There’s only a handful of HDD crossings in the world that have ever been attempted greater than 12,000 ft. There were a lot of challenges related to just that aspect alone.”
“We hit them right on the ends,” says Michels Directional Crossings operations manager Jeff Mueller. “The pilot holes matched up perfectly. We really didn’t do the intersect operations because it was self-intersecting, if you want to call it that. As a company, Michels has done more than 200 intersects and [attained] tip-to-tip about a half dozen times. It’s pretty rare.”
The Houston Ship Channel is part of the Port of Houston — one of the busiest seaports in the United States, serving as the conduit for ocean-going vessels between Houston-area terminals and the Gulf of Mexico, as well as serving an increasing volume of inland barge traffic. According to information on the channel’s website, the seaport is a 25-mile-long complex of diversified public and private facilities located just a few hours by ship from the Gulf of Mexico.
One of the challenges of working in such a busy and congested area like the Houston Ship Channel is the number of pipes that are already buried under it. The design for this project was locked in and good to go until a few weeks before actual drilling was to commence. “Between the time that the project was designed and the time we were onsite to do the project, there were actually two other lines installed that were going to be interference to the original design,” explains Don Mueller, assistant operations manager at Michels Directional Crossings and in charge of the project’s day-to-day management. “We checked in with One-Call and were told that a new line was installed three months [earlier]…We had to re-design on the fly to avoid those new lines.”
The overall project engineer was Universal Pegasus but Michels participated in the HDD portion of the design and development.
Michels set up two of its 1.2 million-lb rigs (aptly named Hercules) on each side of the channel to complete the intricate pilot hole intersect, traversing the drill strings along a narrow and congested right of way. The pilot hole from the entry side was 5,562 ft and the one coming from the exit side was 6,897 ft.
The HDD alignment went through a mix of soil formations, ranging from sand, silts, marine sediment, with a large percentage of penetrating swelling clay, ranging from loose to very dense — quite the array of soil conditions to contend with. McGuire notes that the swelling clays and changing formation were a critical challenge and could have spelled disastrous results for the project if not properly handled through a well thought out and implemented drilling fluids program. Headed up by Michels drilling fluids engineer Rick Zavitz, this program proved to be a critical component so that the annular circulation was maximized and thus reducing the risk for pipe seizure.
“We definitely had to stay on top of it,” Don Mueller says. “With the swelling clays, the drill pipe would get tight after days of work. The mud program played a big role in keeping that free so we could work with the lengths.”
Michels carefully employed critical drilling techniques and specialized drilling fluid from CETCO and M-I Swaco that not only allowed the pilot hole to intersect precisely on the ends near the middle of the crossing but that also achieved full drilling fluid circulation nearly 100 percent of the time on both the pilot hole and reaming operations — a huge accomplishment in drilling circles.
McGuire notes that during the pilot hole drilling, Michels implored to Phillips 66 to allow the crews to move to a 24/7 work schedule on its property to ensure the integrity of the hole was intact. This was due to the changing soil and drilling conditions. “The string torque was getting elevated and we needed to work 24/7 to keep [the string] moving,” McGuire says. “Had [Phillips 66] not allowed us to do that, there’s a good possibility we would have had a lot of problems and wouldn’t have been successful.”
Michels used a SlimDril International DrillGuide GST gyroscopic steering tool with annular pressure monitoring capability on both Hercules rigs to assist with critical steering along the alignment, which went 240 ft below sea level to avoid existing lines and allow for a proper drilling cover. A ParaTrack system from Vector Magnetics was also deployed at various times during the pilot hole.
Jeff Mueller notes that the crew didn’t have a geotechnical report to rely on when they drilled in such deep depths. “By using gyro tools, you are able to drill these distances without having to put your surface cables down, which would have been a challenge because of the marine environment,” he says.
The limited right of way was also a point of concern for Michels due to the space available to lay out the steel pipe for pullback. The pipe string weighed 93.5 lbs per foot and had an overall weight of more than 1.16 million lbs. This long, heavy string had to be carefully handled to be pulled through the hole. Initially, Michels had been given space for nine tie-welds, which was later reduced to four as Phillips 66 was instrumental in obtaining critical additional work space. Because the pull loads continued to increase with each shutdown to weld, it might have increased beyond a manageable force had additional tie-ins been necessary.
“The pullback area was really limited,” McGuire says. “We initially started with nine tie-in welds and we expressed concern over that and worked with [Phillips 66] to secure additional work space, which we got a few weeks before the pullback.
“Pulling back [that amount of pipe] in sections is pretty amazing when you consider it wasn’t that long ago when [drillers] and the industry were absolutely adamant that you had to have it one continuous section to pull it back,” he adds. “And here we are. First, we contemplated doing it in nine sections and we were fortunate enough to get it down to four. That’s pretty phenomenal in itself. You really don’t know until you make that final weld if you are going to get pulling again. Always a risk.”
The Michels team lauded Phillips 66 for success in this project, saying it was an outstanding partner in its response to the team’s needs for additional work space and facilitating its 24-hour pilot hole operations. Troy Construction, hired by Phillips 66 to support the HDD operations, provided assistance by handling site prep, product line string out, testing, coating, welding, pullback pipe handling and coordination.
Sharon M. Bueno is managing editor of Trenchless Technology.